The use of tufting machines for creating tufted articles, for example tufted carpet, is wellknown in the art. In conventional tufting machines, a reciprocating needle bar carries a plurality of aligned needles thereon, the needles being constructed to reciprocably penetrate a backing material passing transversely underneath the needle bar through a tufting zone. As the needles penetrate the backing material, they carry a yarn therethrough, whereupon the yarn is caught either by a looper to create a tufted pile article, or by a looper/hook moved in time relationship with a knife to create a loop of tufted material which is then cut to create a cut pile article. It is by this process, for example, in which tufted cut pile carpeting is made.
Early tufting machines used mechanical devices to reciprocate the needle bar, the loopers, or hooks and the looper/knife arrangement of the machine all of which are known as gauging elements to those familiar with the art, in timed relationship with one another. Thus, in early tufting machines a main drive shaft was rotated by a drive source, most commonly a motor, with the rotation of the tufting machine drive shaft being used to reciprocate the needle bar toward and away from the tufting zone, as well as moving the looper, and/or looper/knife mechanisms in timed relationship with the needles passed into the tufting zone. Early examples of tufting machines used eccentric cams mounted on the tufting machine drive shaft to reciprocate a push rod attached to the needle bar for reciprocating the needles in turn, and using either push rods or straps engaged with additional eccentric cams on the main drive shall of the machine to operate the looper and/or looper/knife mechanisms. Although these tufting machines have proven to be durable and capable of creating a high quality tufted product, the problem with these machines has been the inherent limitations of the mechanical connection or interlinking of the operation of the needle bar, the looper drive, and the knife drive which resulted in increased mechanical drag and led to the creation of heat and increased friction, which in turn led to increased wear and vibration in the drive train, all of which resulted in diminished production efficiency as well as increased machine down time and maintenance/repair costs required to keep the tufting machines in proper working order.
An example of an early tufting machine which uses this kind of mechanical drive system for the creation of tufted products is disclosed in U.S. Pat. No. 3,361,096 to Watkins, as well as in British Patent No. 1,507,201, and British Patent No. 1,304,151. In the effort to get away from using cams with straps or push rods, the use of belt driven components of tufting machines has developed. An early example of this is the multiple stroke looper mechanism for a stitching machine disclosed in U.S. Pat. No. 4,419,944 to Passons, et al. Passons, et al. teach the use of a drive chain passed over a sprocket on the tufting machine drive shaft and a spaced second sprocket to which an eccentric cam shaft is attached, the eccentric cam shaft being used to reciprocate a push rod for rocking the loopers disposed within the tufting zone back and forth with respect to the reciprocation of the needle to create longitudinal rows of stitching in a base fabric in which the looper is driven through two or more strokes for each stroke of the needle in a stitch cycle. In Passons, et al., however, an eccentric cam was still employed on the tufting machine drive shaft for moving a push rod to reciprocate the needle bar, and an eccentric cam mounted in close proximity to the tufting machine drive shaft was still used to drive the loopers in timed relationship thereto, thus requiring the use of a relatively long push rod/crank to rock the loopers with the resultant problem of mechanical vibration, stress, and wear in the looper drive train. Although Passons, et al. represented a novel advance in the art, the problem of using a primarily mechanical link system in tufting operations persisted, which did not allow for the increased tufting speeds and serviceability demanded in the tufting industry.
U.S. Pat. Nos. 4,586,445, and 4,665,845, to Card, et al., respectively, disclose a high speed tufting machine in which a flexible timing belt is used to drive the needle bar by transmitting the rotation of the tufting machine drive shaft to an offset sprocket, the sprocket being one of a series of aligned sprockets along the length of the tufting machine and having a push rod fastened thereto for reciprocating the needle bar with respect to the tufting zone. These two patents to Card, et al. represented a significant advance in the art in allowing still greater production speeds in the creation of tufted products because higher needle bar speeds were now attainable, however Card, et al. did not focus on how the looper drive shaft and the knife drive shaft, if one was present, would be moved in timed relationship with the reciprocation of the needle bar to take full advantage of the improved speed feature of the needle bar drive system.
The tufting machines taught by Passons, et al., and by Card, et al., were followed with the patent to Neely, et al., U.S. Pat. No. 5,513,586 in which a belt driven looper drive assembly was disclosed. In Neely, et al., a looper drive assembly is spaced from the main drive shaft of the tufting machine, with a flexible timing belt encircling a pair of sprockets used to rotate a spindle assembly. The spindle assembly has an eccentric cam mounted on the end thereof, to which a push rod is pivotally fastened for transmitting the rotational motion of the tufting machine drive shaft, through the spindle shaft, into a reciprocating motion whereby a lever is fastened to the push rod for transmitting this reciprocating motion into a rocking motion of the looper drive shaft.
However, neither Neely, et al., nor the patents to Card, et al., or Passons, et al., focused on improvements to tufting machines used for the creation of a cut pile tufted loop in which a series of knives, one knife for each looper or hook, is provided and moved in time relationship with the looper in order to cut the tufted pile, as known in the production of tufted cut pile carpeting and other similar articles. What is needed in tufting machines used for the creation of cut pile articles is a tufting machine which allows for increased production rates, improved serviceability of components, reduced manufacturing costs, and which will allow for the precision adjustment of the gauging elements, to include the loopers and the hooks/knives, with respect not only to each other, but with respect to the tufting machine drive shaft so that the loopers and knives are moved in precise relationship with respect to the reciprocating needles of the tufting machine, and off of which the entire tufting operation is keyed.
In conventional cut pile tufting machines, separate drive assemblies have been used for powering the looper drive shaft and knife drive shaft of the tufting machine, one each of these mechanisms being provided for the looper and knife drive shafts at both ends of the machine across the width of the tufting zone, so that two looper drive systems, and two knife drive systems have commonly been employed in the industry. For example, Neely, et al. teach only a looper drive assembly so that separate knife drive assemblies are still required if the device of Neely, et al. is to be used in a cut pile tufting machine. Moreover, and although Passons, et al. and Neeley, et al. have disclosed belt driven drive systems, these systems focus only or drive systems for loop pile tufting machines in which the loopers do not have the same loading requirements which exist in cut pile production in which a knife blade is repeatedly engaged with the looper and the yarn carried thereby at a high rate of speed as the looper is simultaneously drawn back from the needle to create the pile of yarn to be cut. This results in greatly increased loads on the loopers or hooks of a cut pile system, and requires the ability to precisely adjust the hooks for loopers with respect to the knives, and vice versa, and each with respect to the needle bar so that still higher production rates can be attained.
What has been needed, therefore, but seemingly unavailable in the art is an improved tufting machine belt driven drive assembly for driving the gauging elements, the hooks and knives, of a cut pile tufting machine which allows for the precise adjustment of the loopers and knives with respect to one another, and with respect to the tufting machine drive shaft, but yet which also provides a reduced mass to allow for increased operational speeds, and improved serviceability. What has also been needed, but unavailable in the art, is a reduced mass looper and knife drive system which is constructed to accommodate the increased loading of a looper in a cut pile tufting machine, and which allows for the precise adjustment of the loopers and knives with respect to one another. What is also needed is a belt driven tufting machine drive assembly for powering both the loopers and knives of a tufting machine which allows for precision stroke control of the spaced looper and knife drive assemblies at each end of the looper and knife drive shafts of the tufting machine to eliminate any torque stress loading, or torque within the looper and knife drive shafts for improved machine reliability and a high quality tufted cut pile article.
The known devices are not constructed to perform these tasks, and they fail to suggest how this may be reasonably accomplished. What is still needed, therefore, is an improved belt driven tufting drive assembly constructed to drive both the loopers and the knives of a cut pile tufting machine which provides for a simple, yet durable and rugged apparatus which is simple in design and inexpensive to construct, which allows for improved serviceability, and allows for improved production rates demanded in high speed tufted cut pile manufacturing operations.